The present invention generally relates to battlefield eletronics, and more particularly relates to battlefield transmitters and receivers, and even more particularly relates to mechanically robust air-dropped, artillery-launched, and infantry-deployed battlefield wireless LANs.
In recent years, wireless local area networks (LANs) have gained popularity in many industries. The battlefield is yet another potential arena in which wireless LANs could be deployed. The U.S. Government has proposed a program known as WINS, in which wireless LANs will be used in battlefield situations. However, the battlefield often necessitates extraordinary robustness and ruggedness requirements when compared to design requirement associated with consumer or industrial electronics. For example, many battlefield electronic devices are either air dropped or launched from a cannon. Components of wireless LANs would be no exception.
The antennae used for battlefield electronic devices also must meet extraordinary requirements. The proposed WINS wireless LAN will use numerous wireless transceivers scattered over the surface of the ground. The wireless transceivers will communicate with each other to form a LAN, and they will also communicate with sources and destinations of information such as mobile communication devices, either handheld by infantry, coupled to vehicles such as tanks, trucks, or remotely piloted vehicles. The wireless LAN may also receive information from manned and unmanned surveillance devices, etc. The general purpose of the WINs wireless LAN is to provide an army with a flexible, reliable, and robust system to allow secure terrestrial communication over a defined battlefield or other region.
One proposal has been to utilize a xc2xc wave monopole antenna in association with the wireless LAN transceiver chassis. Such a monopole antenna would often be on the order of 8.4 inches tall plus the height of the transceiver chassis. It would require a xc2xd wavelength ground plane (approximately 17 inches for a 350 MHz transceiver). While a xc2xc wavelength monopole antenna could be used, it does have several disadvantages. The 8-inch height in addition to the transceiver chassis could make the wireless LAN transceiver module easier to be visually detected and disabled by approaching infantry. The xc2xd wavelength ground plane is often too large to have a fixed plate and post placement mechanically deployed ground wires, while theoretically capable of serving as a ground plane, are often mechanically unreliable in practice. Also, such monopole antennae are readily susceptible to orientational problems, such as when an antenna lands on its side, and transmits up to the sky, where it can be more readily detected by air surveillance, instead of transmitting horizontally to the users on the ground. Additionally, polarization mismatch (i.e., cross polarization) can be a serious problem in such cases.
While a helical monopole antenna would have a shorter height characteristic, it would still suffer from many of the same shortcomings as does the xc2xc wavelength monopole whip antenna. In addition, the helical monopole has a lower radiation efficiency and is more difficult to impedance match.
Conical and cylindrical slot antennae have been proposed in the past for various military uses. U.S. Pat. No. 6,098,547 entitled Artillery Fuse Circumferential Slot Antenna For Positioning and Telemetry by James B. West, issued on Aug. 8, 2000; U.S. Pat. No. 4,305,078 entitled Multifrequency Series-Fed Edge Slot Antenna by Jones et al. issued on Dec. 8, 1981; and U.S. Pat. No. 4,051,480 entitled Conformal Edge-Slot Radiators by Reggia et al. issued on Sep. 27, 1977, all describe slot antennae used in military applications.
While these slot antennae have been used extensively in the past, they do have some shortcomings if proposed for battlefield LAN use. First of all, none of these above-mentioned antennae designs addresses battlefield deployable wireless LANs and the antennae requirements associated with such an application. None of these references suggests how one might aerially deploy wireless LAN transceivers across the surface of a battlefield and maintain proper antennae orientation (co-polarized reception and transmission with the LAN) and transceiver integrity.
Consequently, there exists a need for methods and systems for deploying wireless LANs on a battlefield in an efficient manner.
It is an object of the present invention to provide a system and method for deploying a wireless LAN in a battlefield or non-battlefield application in an efficient manner.
It is a feature of the present invention to utilize a quasi-conical/quasi cylindrical antenna/housing.
It is another feature of the present invention to include an antenna/housing shape which has a non-stable orientation in non-operational orientations.
It is an advantage of the present invention to achieve improved efficiency in battlefield deployment and use of wireless LANs.
The present invention is an apparatus and method for providing a wireless LAN in a battlefield which is designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out in a xe2x80x9cwasted transceiver-lessxe2x80x9d manner in a sense that the number of transceivers which are unusable in the battlefield because of improper orientation and other deployment and use related faults has been greatly reduced.
Accordingly, the present invention is a system and method including a wireless LAN in a quasi-conical/quasi-cylindrical antenna/housing which is not positionally stable in non-operational orientations.